Mold assembly



y 22, 1951 c. A. NICHOLS 2,554,378

MOLD ASSEMBLY Filed Nov. 29, 1947 9 Sheets-Sheet 1 y 1951 I c. A.NICHOLS 2,554,378

MOLD ASSEMBLY Filed Nov. 29, 194? 9 Sheets-Sheet '2 281+ r 1 29'! 43 FTL I l l i v 1 f v w r r- I I g 5'0 Z; I 4 app- "4! (23 INVENTOR.

y 1951 c. A. NICHOLS 2,554,378

MOLD ASSEMBLY Filed NOV. 29, 1947 9 Sheets-Sheet 3 28 I Z'?/ 62 T: 4/-NI! III I a 4 llllll wk/lnlllllli 42 60 1 6J3 L 1- P5] INVENTOR.

y 951 c. A. NICHOLS 2,554,378

MOLD ASSEMBLY Filed Nov. 29, 1947 9 Sheets-Sheet 5 y 1951 c. A. NICHOLS2,554,378

MOLD ASSEMBLY Filed Nov. 29, 1947 9 Sheets-Sheet 6 May/ 144 y 1951 c. A.NICHOLS 2,554,378

MOLD ASSEMBLY Filed Nov. 29, 1947 9 Sheets-Sheet 7 May 22, 1951 c. A.NICHOLS MOLD ASSEMBLY 9 Sheets-Sheet 8 Filed Nov. 29, 1947 I INVENTOR.76444 May 22, 1951 c. A. NICHOLS 2,554,373

MOLD ASSEMBLY Filed Nov. 29, 1947 '9 Sheets- 321961; 9

IN V EN TOR.

Maw 7- 36 @M;

Patented May 22, 1951 MOLD ASSEBIBLY Charles A. Nichols, Anderson, Ind.,assignor to General Motors Corporation, Detroit, Mich., a corporation ofDelaware Application November 29, 1947, Serial No. 788,944

6 Claims. (01. 18-42) 1 2 This invention relates to the art of moldingFig. A is a sectional view on line 10AHIA articles from plastic materialparticularly therof Fig. 10.

mosetting material.

An object of the invention is to reduce the cost of mold equipment byreducing the number of different parts required. In the disclosedembodiment of the present invention this object is accomplished byproviding a mold shell adapted to receive any one of a number of die andknockout pin assemblies respectively comprising parts for supporting aplurality of dies and the knockout pins associated therewith, byproviding a die assembly including a die plate capable of receiving aplurality of interchangeable dies of the same thickness and by providinga knockout-pin assembly including a support to which there can beattached different pin-plates supporting the required knock-out pins.The shell will receive a die-assembly of a certain total thickness equalto the thickness of three components, namely, a die plate, a die locatorplate and a pressure block. Die plates of difierent thickness can beused depending on the thick ness of the dies. Pressure blocks ofdifferent thickness can be used depending on the thickness of the dieplate used and the location of the knock-out pins. The same die locatorcan be used with these different combinations of die plates and pressureplates.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

In the drawings:

Figs. 1 and 2 are plan views respectively of lower and upper mold framesor shells adapted to be operated by a hydraulic molding press.

Fig. 3 is a sectional view on lines A-A of Figs.

Fig. 11A is a fragmentary view in the direction of the arrow HA of Fig.11.

Fig. 14 is a sectional view on line M-l4 of Fig. 13.

Figs. 15, 16, 17, and 18 are views taken respectively on the lines l5l5,I8l6, l1--ll, and |8|8 of Fig. 9. 1

Fig. 16A is a fragmentary view looking in the direction of arrow [6A ofFig. 16.

Fig. 19 is a perspective view of a part selected as an example of onekind of work for which a mold constructed in accordance with the presentinvention is adapted.

Fig. 20 is a perspective view of the same part inverted.

Fig. 21 is a plan View of the lower die for molding the parts shown inFigs. 19 and 20.

Fig. 22 is a View in the direction of arrow 22 of Fig. 21.

Fig. 23 is a view on line 23-23 of Fig. 21.

Fig. 24 is a plan View of the lower die carrier.

Fig. 24A is a fragmentary view in the direction of arrow 24A of Fig. 24.

Figs. 25 and 26 are sectional views taken respectively on the line 25-25and 25-46 of Fig. 24.

Fig. 27 is a plan View of the upper die comprising parts A, B and C inassembled relation.

Fig. 28 is a view of die part C looking in the direction of arrow 28 ofFig. 2'7.

Fig. 29 is a View of part C looking in the direction of arrow 29 in Fig.28.

Fig. 30 is a View of die part B separated from the other parts shown inFig. 27.

Fig. 31 is a view in the direction of arrow 3| of Fig. 30.

Fig. 32 is a view in the direction of arrow 32 of Fig. 30.

1 and 2 showing the lower and upper shells in Fig. 33 is a view of diepart A separated fromthe closest relation. the other parts shown in Fig.2'7.

Fig. 4 is a fragmentary view in the direction Fig. 34 is a view in thedirection of arrow .34 of the arrow 4 of Fig. 3. of Fig. 33.

Fig. 5 is a view similar to Fig. 3, but taken on Fig. 35 is a view inthe direction of arrow 35 the lines BB of Figs. 1 and 2. of Fig. 34.

Figs. 6 and 7 are side views respectively of the upper and lower dieassemblies in separated relation.

Fig. 8 is a view in the direction of arrow 8 of Fig. 6.

Fig. 9 is a sectional view on line 0-0 of Fig. 8 showing the upper andlower die assemblies in engaging relation.

Figs. 10, 11, 12 and 13 are views on linesv [FL-l0, H-H, l2--|2 andI3-|3 respectively of Fig. 9.

Fig. 36 is a fragmentary side view partly in section of a press foroperating the molds shown in the preceding figures the parts in sectionbeing taken in the vertical plane which intersects the axes of posts 2|and 22.

Referring to Fig. 36, the press has a. base 20 which supports posts 2|and 22 which guide for vertical movement a press head plate 23 which isoperated by a hydraulic servomotor not shown.

A table 24 is pivotally supported by the post 22,.

said table being secured to a bearing sleeve journalled on the post. Theweight of the table and parts supported thereby is taken by a stepbearing 23 carried by a bracket 27. The base 20 supports a hydraulicservomotor comprising a cylinder and a piston 3| whose rod 32 carries anadjustable screw 33 secured in the desired position of verticaladjustment by a nut 34. Screw 33 has a T-head 35 for a purpose to bedescribed. Table 20 supports hydraulic servomotor including a cylinder36 within which there is a piston connected with a rod 31 which isconnected with a T-head 38 for a purpose to be described.

The press head plate 23 supports a heat insulating plate 28 and a metalplate 29. Plate 29 supports an upper mold shell assembly 40 whichcomprises a ring 4| and a shell 42 which screws 43 attach to the ring4|. Shell 42 is provided with three notches 44 (Figs. 2 and 3) throughwhich compressed air can be blown for clean-out purposes. Shell 42 hasan internal annular flange 45 having plane surfaces 46 and 41. Notches48 and 49 receive a key 50 and notch 5| receives a key 52. Three notches53 each receive a clamp 54 retained by a screw 55. The assembly 40 issecured to the plate 29 shown in dot dash lines in Fig. 2 by clamps 55and screws 51.

The shell 42 is heated by a plurality of heating elements (Fig. 5)received by holes 3| (Fig. 2) in shell 42. Holes 62 provided by a plate4| in alignment with holes 6| may each receive a rod for driving out aheater element 90 in case it sticks in the shell 42. The elements I; areretained by clamping segments 63 (Figs. 3 and 5) which are retained byscrews (not shown) passing through threaded holes 04 (Fig. 2) in theshell 42. The wires leading to the heater element may be brought outthrough notches 05 (Fig. 5). Three screws 56 secure to the shell 42three pilot pins 61 which are adapted to be received by holes 67' in thelower shell 42'. 7

Shell 42 is a part of a' lower shell assembly 40 which comprises partssimilar to those of the upper shell assembly 40. The parts of the lowerassembly which are similar to the upper assembly have the same referencenumerals with the prime afiixed. The plate 4i of the lower assemblytogether with a heat insulating plate 28' is secured to the table 24 byclamps 56 and screws 51' shown in dot dash lines in Fig. 1. The table 24supports two of the assemblies 40 and, in order to locate theseassemblies properly, the table is provided with two diametricallyopposite holes '10 each of which receives a ring II which screws I2attach to plate 4|.

Each lower assembly is adapted to receive a lower die assembly such asshown in Fig. 7 which includes a sub-assembly of plates 80, 90 and ablock I00 shown respectively in Figs. 10, 11 and 12. These parts arefitted together as shown in Fig. 9 and the block I00 rests upon thesurface 41 of the flange 45' of shell 42'. These parts are. located inproper alignment by key 52 received by grooves 8| 9| and |0Irespectively of the parts 30, 90 and I00. The threeclamps 54 whichproject into the grooves 82 of plate hold the parts Within the shell 42when the screws 55 are attached and tightened.

The plate 80 has a plurality of holes 83 each for receiving a lower diecarrier 84 (Figs. 24 to 26) having a central opening 85 for receivingthe lower die D (Figs. 21-23). Each carrier 34 has a circular flange 84areceived by a hole 9| in locator plate 90.

To prevent turning the carrier 84 in plate the latter is provided withkey slots 92 each of which receives a key 93 (Fig. 9) which is receivedby the notch 84b in flange 8411. Each carrier 84 has a groove 88 whichaligns with a groove 0? (Figs. 10 and 10A) provided by plate 80, saidlatter groove extending into a central bore 88 which provides a portionof an injection cylinder. Bore 88 is in alignment with a bore I08 in theblock I00 (Figs. 9 and 12) said bore being surrounded by a flange |08a(Fig. 9) which fits into the plates 90 and 30. The walls of bore I08 aregrooved at I07 to provide for the relief of vacuum. The cylinderprovided by bores I08 and 88 receives a piston or ram I30 (Figs. 3 and5) which a screw I3| attached to a rod I32 having a head I33 providedwith a T slot I34 defined by arcuate surfacesv I35, I 36 and I3? (Fig.4) whose center of curvature is the axis of rotation of the table 24.The T-slot I34 is adapted to receive either the T-head 35 of the screws33 or the T- head 38 associated with the cylinder 36 as shown in Fig.36. To prevent rotation of the head I33 the rod I32 and the stem of theram I30 there is provided a key slot I 40 which receives a key I4| whichas shown in Fig. 9 extends through a sleeve |2| located centrally of thepin-plate supporting plate I20 said key extending also into a notch I22of plate I20. Sleeve |2| is retained upon plate I20 by a pin-plate III!which screws II I secure to plate I20. Plates H0 and I20 supportknockout pins H2 and I I3 (Fig. 1-3) the heads of which have flats so asto be engaged by a common key H4 received by a key slot H5 in plate IIO.Therefore the rods I I2 and I I3 cannot turn. The heads of these rodsare received by counterbores in the plate H0 and are retained byattaching pin-plate H0 and assembled pins H2 and II3 to the plate I20 bymeans of screws III. The rods II2 and II3 extend upwardly through holesI02 and I03, respectively, in block I00 (Fig. 12). Rods |I2 terminate inblades H213 and rods 3 terminate in blades I |3B which as shown in Fig.11 slide along grooves in the die D for the purpose of ejecting the workmolded by said die. Only one set of pins |I2, I I3 is shown assembledwith the plate I I0 in Fig. 13. The holes for. pins II2 are marked H0,and the holes for pins II3 are marked I I1.

Upon the plate I23 there rests four push-back pins 89 which pass throughnotches H0 in plate I I through holes I05 in block I00, through holes 95in plate 9 and through plate 30. The ends of these pins 09 appear inFig. 10. The knock-out pin assembly which includes plates II3 and I20and pins H2 and II3 can be assembled within the lower part of the shell42 below the surface 46' before the shell 42' is attached to plate 4| bythe screws 43. However before this assembly is made, the ram I30 islocated upon the sleeve I2| with the key slot I40 in the stem of the ramreceiving the key I4I. Then the rod I32 is located with its slot I49receiving the key |4|. When these parts are thus located, a dowel pinI30 attached to rod I32 will register with a dowel pin hole I39 providedby the ram I33. Then the screw I3! is assembled and tightened to securethe ram I39 and the rod I32. Then the knoek-out-pin assembly of platesH0 and I20 and pins H2 and II3 and the assembly of ram I30 and rod I32can be assembled with the plate :lI'. Thereafter the plate M can beassembled with the shell 42 because the ring I! will clear the stem headI33.

The upper die assembly (Fig. 6) comprises die assembly plates I30, I90and block 200 and knockout-pin assembly block 200, pin-plate 2I0, andpins 2 I2. Parts I00, I90 and 200 of the upper die assembly aresimilarto parts 80, 9B and I re spectively of the lower die assembly.The block 200 contacts the surface 41 of'flange 45. Plates I80 and I90and block 200 are provided respectively with grooves I 8I, I9I and 29Iwhich receive key 52 which locates these parts. Plate I80 is providedwith grooves I82 which receive the clamps 54 which are secured by screws55. Thus the parts I80, I90 and 209 are detachably secured within theshell 42.

The plate I80 is provided with holes IE3 each for receiving assembly ofupper die parts com prising the parts A, B and C shown in Figs. 27 toinclusive. The dies provide openings for the knockout pins 2I2. Theplate E80 provides holes for receiving the push-back pins I89.

Fig. 16 shows that plate ms is provided with holes I93 for receiving thedie parts A, B and C through which the knockout pins 262 extend. PlateI99 is provided with key grooves I92 each receiving keys I94 (Fig. 9)which fit into the notches Bn (Fig. 27) of the die B. Plate I90 hasopenings through which the push-back pins I89 extend.

Fig. 17 shows that a block 209 is provided with holes 202 for receivingthe knockout pins 2H? and with holes 203 for receiving the pushback pinsI89. of each hole 203 is enlarged at 234 to receive a cross pin 205 ineach pin H39 which extends beyond the periphery of the pin ass so that.when the upper die is separated from the lower die,

the pins I89 will not drop out because the cross pins 205 will be caughtby the plate I99.

Fig. 18 shows pin-plate 210 which is provided with notches 2l3 forreceiving the upper ends of the pushbaok pins I89 which may engage theblock 220. Plate 2H is provided with counterbored holes for receivingthe head ends of the knockout pins 2 I2. These pins are retained whenpin-plate 2I0 is secured to pin-plate supporting block 220 by screws 2M(Fig. 8). Block 220 has a groove 22! for receiving the key 50 (Fig. 3)and with holes 222 each for receiving a spring 223 also received byrecesses 2911 (Figs. 3 andfi) in plate 29. The function of the springs223 is to urge the plate 2I0 toward the surface 45 of flange 45 of shell42 when the upper mold rises from the lower mold whereby the knockoutpins 2 I2 strip the Work from the upper die cavities. The parts arestripped from the lower die cavities at the loading station by upwardmovement of the piston in cylinder 36 which head 38 connects with the Tslotted head !33 of the rod I32. When these parts are caused to move upthe head I33 engages the plate I20 thereby causing the pins H2, H3 tomove upward to eject the work from the lower die cavities. When theupper mold is lowered upon the lower mold, the push-back pins I89 of theupper mold engage the push-back pins 89 of the lower mold assemblythereby causing the ejector pins to be retracted from the mold cavities.Die plates 80 and I80 accommodate different dies of the same diameterand thickness. If dies of other thickness are used, die plates of therequired thickness can be substituted, and pressure blocks of suitablethickness and knockout-pin hole spacing can be substituted so that thetotal thickness of the die assembly will be the same. The dies ofvarying thickness can have flanges of the same thickness so that thesame die-locator plates 90 and I90 can be used. The same blocks 220 andI20 can be used with As viewed in Fig. 9, the lower portion 1 variousdie assembly combinations, and will accommodate the required pin plates2I0 and H0 carrying suitably arranged knock-out pins. The same ram I30can be used since no change in in jection cylinder diameter is requiredfor work which can be molded by die assemblies which can be accommodatedby shells of a certain diameter.

Satisfactory heat transfer for the shells to the die assemblies requireclose fit. Therefore the heat treatment of the parts should be such thatmetallurgical structure is stabilized so that dimensional relativity isnot afiected by temperature. For example, it is desirable that the thickpressure blocks I00 and 200 fit snugly within the shells so as tooperate eiiiciently to transfer heat from the shells to the dies andalso to function as heat storage bodies which would retard reduction ofdie temperature when the molds are open. It is desirable, after repeateduse of the molds, that these blocks as well as other die plates be aseasily removable from the shell as when first assembled. Therefore theheat treatment should be such as to prevent growth during use.

While the embodiment of the present invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scop of the claims which follow.

What is claimed is as follows:

1. A mold assembly comprising a shell adapted to be mounted on the baseor head of a molding press, a die assembly which is detachably securedin the shell and Which provides an injection cylinder and mold cavitiesand runner grooves which extend from the cylinder to the mold cavities,a knock-out-pin assembly housed within the shell and including knock-outpins received by the die assembly, a ram located in the cylinder andguided for movement by the knock-out pin assembly, a member for movingthe ram and engageable with the knock-out-pin assembly in order to moveit when molded parts are to be ejected, and push back pins extendingthrough the die assembly and operatively connected with theknock-out-pin assembly.

2. A mold assembly comprising a cylindrical shell and a supporting plateattached thereto, said shell providing an internal annular flange, acylindrical die assembly comprising a die plate, a die-locator plate anda die pressure block, said assembly fitting within the shell with thedie plate outermost and the block innermost and contacting the flange,means detachably connected with the shell and engaging the die plate toretain the die assembly within the shell, means engaging the shell anddie assembly members to maintain them in proper alignment said die platehaving circular holes, cylindrical dies received by said holes, meansengaging the 10- cator plate and the dies to locate themcircumferentially, and a knock-out pin assembly comprising knock-outpins extending through the pressure block and into the dies, a pin-plateconnected with the pins, a pin-plate support to which the pin-plate isattached, said pin-plate support being received within the shell on theside of the flange remote from the pressure plate, means engagin thepin-plate support and the shell to prevent rotative displacement whilepermitting the support to move axially of the shell, and push-back pinsengageable with the pin-plate support and extending through the dieassembly.

' 3. A mold assembly comprising a cylindrical shell and a supportingplate attached thereto, said shell providing an internal annular flange,a cylindrical die assembly comprisin a die plate, a die-locator plateand a die pressure block, said assembly fitting within the shell withthe die plate outermost and the block inner-'- most and contacting theflange, means detachably connected with the shell and engaging the dieplate to retain the die assembly within the shell, means engaging theshell and die assembly members to maintain them in proper alignment saiddie plate having circular holes, cylindrical dies received by saidholes, circular holes in the locator plate receiving annular flangesprovided by the dies, keep engaging notches in said flange and groovesin the locator plateto locate the dies circumferentially, and aknockout-pin assembly housed within the shell and including knock-outpins received by the die a assembly, and push back pins extendingthrough the die assembly and operatively connected with theknock-out-pin assembly.

4. A mold assembly comprising a shell adapted to be mounted on the baseor head of a molding press, a die assembly detachably secured therein,and providing an injection cylinder connected by runner grooves with themold cavities, a knock-out-pin assembly comprising knock-out pinsextending into the dies,- a pinplate connected with the pins, apin-plate sup port to which the pin-plate is attached, means engagingthe pin-plate support and the shell to prevent rotative displacementWhile per m'itting the support to move axially of the shell, a sleevesupported by said support in alignment with the cylinder and retainedupon the support by the pin-plate, a rod guided by the sleeve andproviding a ram located in the cylinder, a member provided by the rodfor receiving an applied force and engageable with the pin-plate supportto efiect ejection of molded parts, and push back pins extending throughthe die assembly and operatively connected with the knock-out-pinassembly.

5. A mold assembly comprising a shell adapted to be mounted on the baseor head of a molding press, a die assembly detachably secured therein,and providing an injection cylinder connected by runner grooves with themold cavities, a knockout-pin assembl comprising knock-out pinsextending into the dies, a pin-plate connected with the pins, apin-plate support to which the pinplate is attached, .means engaging thepin-plate support and the shell to prevent rotative dis.- placementwhile permitting the support to move axially of the shell, a sleevesupported bysaid support in alignment with the cylinder and retainedupon the support by the pin-plate, a rod guided by the sleeve andproviding a ram located in the cylinder, a member provided by the rodand engageable with the support and having a T-slot for receiving eitherof two T-head members, one of which is actuated to move the ram forinjection purposes, the other of which is actuated to move the supportfor ejection purposes, a longitudinal groove in the rod, a key supportedby the sleeve and received by the groove, and push back pins extendingthrough the die assembly and operatively connected with theknock-out-pin assembly.

6. Cooperating mold assemblies adapted respectively to be attached tothe bed and movable head of a molding press, said assemblies eachcomprising a shell, a die assembly removably secured in each shell, aknock-out pin assembly housed for movement in each shell, the dieassembly of one of the mold assemblies providing an injection cylinderand runners leading therefrom to the die cavities, .a'ram in saidcylinder, a rod connected with the ram and guided by the associatedknock-out-pin assembly, a force receiving member provided by the rod andengageable with the knock-out pin assembly to effect ejection of moldedparts, the die assembly of the other mold assembly providing a closurefor the cylinder when the die assemblies are engaged, said other moldassembly having spring means to actuate its knock-out-pin assembly, andpush back pins provided by both die assemblies and operatively connectedwith the knock-out-pin assemblies.

CHARLES A. NICHOLS.

REFERENCES CITED The following references are of record in'the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,909,253 Claus May 16, 19331,961,941 Pack June 5, 1934 2,419,089 Quarnstrom Apr. 15, 1947

